Rotatably reversible connector for electric circuit breaker

ABSTRACT

A connector means is provided for electrical connection of a conductor to a circuit breaker which may be selectively mounted at its top or bottom to a panel. A generally cylindrical connector body has an opening in a planar portion to accommodate a clamping screw. Upon removal of the clamping screw, slots in the connector body accommodate insertion of the end of a screwdriver to facilitate rotation of the connector body.

United States Patent [151 3,679,854

Burd 1 July 25, 1972 [541 ROTATABLY REVERSIBLE ls'Ei References 6m CONNECTOR FOR ELECTRIC CIRCUIT UNITED STATES PATENTS BREAKER Inventor: Thomas A. Burd, Cedar Rapids, Iowa Assignee: Square D Company, Park Ridge, lll.

Filed: June 18, 1971 Appl. No.: 154,388

U.S. Cl ..200/l66 BB, 339/272 R, 200/166 CT, 200/168 R Int. Cl ..H0lh 9/00, HOlh 9/54 Field of Search ..339/272 UC, 272 R, 32 R, 32 M;

200/168 C, 166 CT, 166 R, 166 BR, 168 R 2,958,068 l0/l960 Lipinski.... .....339/272 UC X 2,795,766 6/1957 Dyer et ....339/l98 N X 2,732,535 l/l956 Hammerly ..339/272 UC Primary Examiner-H. 0. Jones Attorney-Harold J. Rathbun et al.

[57] ABSTRACT A connector means is provided for electrical connection of a conductor to a circuit breaker which may be selectively mounted at its top or bottom to a panel. A generally cylindrical connector body has an opening in a planar portion to accommodate a clamping screw. Upon removal of the clamping screw, slots in the connector body accommodate insertion of the end of a screwdriver to facilitate rotation of the connector body.

4 Claims, 4 Drawing figures PATEEN TEDJM m2 3.679.854

FIG. 4

INVENTOR.

THOMAS A. BURD ROTATABLY REVERSIBLE CONNECTOR FOR ELECTRIC CIRCUIT BREAKER Unit mounted circuit breakers of the type disclosed in US. Pat. No. 3,398,249, issued to Edward P. Dessert on Aug. 20, 1968, are principally utilized for circuit protection when a single circuit breaker is needed and must be mounted on a sheet metal panel or the like. These applications require that the unit mounted circuit breaker be adaptable for mounting at either its top or bottom end, as is well known in the art.

Both line and load side conductors, due to the mounting requirements of unit circuit breaker, must be connected at the sides of the circuit breaker and the means used for connecting these conductors to the circuit breaker must be adaptable for operation in both mounting modes of the circuit breaker. That is, the conductor connecting means must be operable from the bottom when the circuit breaker is top connected and operable from the top when the circuit breaker is bottom connected. The attachment means must also provide rapid and easy attachment of conductors of various sizes and types.

Prior art devices utilize a box like connector having a clamping screw selectively insertable in openings provided in both an upper and lower wall thereof. Such a device is shown is the aforementioned US. Pat. No. 3,398,249. Although this connector properly and efliciently performs its desired function, difliculties have been noticed when conductors made of light, brittle materials, such as aluminum, are used. When such a conductor is pressed between the terminal strap and connector wall having the unused screw receiving opening therein, a portion of the conductor is forced into the opening and the edges of the opening act to create surface knicks and severe stresses which may cause a break in the connected end of the conductor, thereby opening the circuit.

Therefore, it is an object of the present invention to provide a connector for a unit mounted circuit breaker which is useable when the circuit breaker is top and bottom mounted and has only a single clamping screw opening.

FIG. 1 is a side view of a molded case circuit breaker mounted above a panel and with portions of the case broken away to reveal wire connectors therefor in accordance with present invention;

FIG. 2 is an end view taken from the right of FIG. 1 with a cover flange partially cut away;

FIG. 3 is an end view similar to FIG. 2, but showing the wire connector in its operative position when the circuit breaker is mounted beneath a panel;

FIG. 4 is an end view of the wire connector.

Referring to FIGS. 1 and 2, a circuit breaker 11 having a molded case 12 is mounted above a panel 14 by mounting means described in detail in the aforementioned US. Pat. No. 3,398,249, and generally comprising a pair of identical mounting brackets 15 engaging cooperating grooves 16 in the side walls of the molded case 12. Threaded connectors 17 may be used to afiix the mounting brackets 15 to the panel 14.

The circuit breaker 11 has a pair of temrinal straps 19 for external electrical connection of the circuit breaker 11. Each terminal strap 19 is held within a diminished end portion 21 of the molded case 12 which has a pair of side walls 22 defining a space 24 therebetween accessible from the top and bottom. lnwardly turned outer edges of the molded case end portion 21 form end flanges 25 therefor.

Referring now to FIG. 4, a connector 26 is illustrated which is made in accordance with the present invention. A generally annular connector body 27 is preferably formed by extrusion and is generally cylindrical in shape. A planar portion 29 of the connector body 27 has a threaded opening 30 extending therethrough. An outer surface 32 of the connector body 27 has a plurality of circumferentially spaced slots 34 formed thereon, generally parallel to the axis of rotation of the connector body 27. A central opening 35 in the connector body 27 may be generally rectangular in shape with a wall portion 350 thereof having a generally circular shape to facilitate connection of a conductor (not shown). A clamping screw 36 is threaded through the opening 30 to facilitate tightening of the connector 26.

The connector 26 is inserted in the end portion 21 of the molded case 12 during assembly of the circuit breaker 11 with the terminal strap 19 extending into the central opening 35. After the molded case 12 is assembled, the connector 26 is held against removal by the end flanges 25. As can be seen in FIG. 2, if the connector body 27 is aligned with its planar portion 29 upwardly directed, the clamping screw 36 may be readily attached to the connector body 27 and is easily tightened to facilitate conductor attachment.

Electrical connection of a conductor to one of the terminal straps 19 of the circuit breaker 11 is readily accomplished by inserting an exposed end portion of the conductor between the terminal strap 19 and the curved surface 35a of the central opening 35 of the connector body 27. When the clamping screw 36 is tightened, a threaded end portion of the clamping screw 36 presses against the fixed terminal strap 19 and, therefore, causes the connector body 27 to be shifted in a direction toward the head of the clamping screw 36. This closes the distance between the terminal strap 19 and the surface 35a so that the conductor is held tightly between the two smooth surfaces with minimum metal fatigue for the conductor. Loosening the clamping screw 36 allows removal of the conductor from between the terminal strap 19 and the surface 35a of the central opening 35.

When the mounting brackets 15 and threaded connectors 17 are used to mount the circuit breaker l l beneath the panel 14, as is illustrated in FIG. 3, the connector position illustrated in FIG. 2 will no longer permit access to the head of the clamping screw 36 for connecting or disconnecting a cond uctor. Therefore, the orientation of the connector 26 must be shifted substantially so that access may be had to the clamping screw 36 from the bottom of the circuit breaker l I.

Re-orien tation of the connector 26 is preferably accomplished before the circuit breaker l l is mounted on a panel 14 in its new position. First the clamping screw 36 is removed. Next the connector body 27 is rotated. This is readily accomplished by inserting the end of the screwdriver (not shown) into one of the slots 34 and exerting a force to cause the connector body 27 to rotate around the terminal strap 19. The

screwdriver may be shifted from slot to slot until the connector body 27 has been rotated the required 180. Finally, the clamping screw 36 is re-threaded into the opening 30 in the planar portion 29 of the connector body 27. In this manner the connector 26 is repositioned for access from the bottom of the circuit breaker l I.

It is clear that modifications of the reversible connector of the present invention are possible without departing from the spirit thereof. For example, instead of providing slots 34 on the outer surface 32 of the connector body 27 to facilitate rotation, and end face of the connector body 27 may be diametrically slotted to accommodate the end of a screwdriver which, when rotated, causes a corresponding rotation of the connector body 27.

I claim:

1. In a circuit breaker having a molded case and a tenninal strap for electrical connection to a conductor, connector means comprising a generally annular connector body rotatably received on said terminal strap and having an inner surface, removable clamping means for biasing said inner surface toward said temiinal strap to hold a conductor therebetween, and slot means on said connector body for facilitating rotation of said connector body by use of a tool.

2. A connector means as in claim 1 wherein said connector body has a generally radial opening extending through a wall portion thereof, said clamping means comprises a clamping screw threaded through said opening, and said inner surface is generally opposite said wall portion.

3. A connector means as in claim 1 wherein said molded case has an end portion comprising a pair of spaced, generally parallel side walls on opposite sides of said connector body, and flange means on said side walls for maintaining said connector body on said temiinal strap.

4. A connector means as in claim 1 wherein said connector body has an outer surface and an axis of rotation and said slot means comprises a plurality of spaced slots on said outer surface, each of said slots being aligned generally parallel to said axis of rotation. 5

i I 1' i 1! 

1. In a circuit breaker having a molded case and a terminal strap for electrical connection to a conductor, connector means comprising a generally annular connector body rotatably received on said terminal strap and having an inner surface, removable clamping means for biasing said inner surface toward said terminal strap to hold a conductor therebetween, and slot means on said connector body for facilitating rotation of said connector body by use of a tool.
 2. A connector means as in claim 1 wherein said connector body has a generally radial opening extending through a wall portion thereof, said clamping means comprises a clamping screw threaded through said opening, and said inner surface is generally opposite said wall portion.
 3. A connector means as in claim 1 wherein said molded case has an end portion comprising a pair of spaced, generally parallel side walls on opposite sides of said connector body, and flange means on said side walls for maintaining said connector body on said terminal strap.
 4. A connector means as in claim 1 wherein said connector body has an outer surface and an axis of rotation and said slot means comprises a plurality of spaced slots on said outer surface, each of said slots being aligned generally parallel to said axis of rotation. 